The present discloser relates to an intake manifold.
The intake manifold disclosed in Japanese Laid-Open Patent Publication No. 2010-196646 is arranged between the first cylinder head of the first bank and the second cylinder head of the second bank in a V-type internal combustion engine. The intake manifold includes an upstream part and a downstream part. The upstream part is located upstream in the flow direction of intake air. The downstream part is located downstream from the upstream part in the flow direction of intake air and coupled to the upstream part. The upstream part has three upstream passages. Each of the upstream passages has a downstream section divided into two subsections by a partition wall. The downstream part has six downstream passages corresponding to the six subsections of the upstream passages.
As the engine operates and thermally expands, the first cylinder head and the second cylinder head of the engine deform away from each other. This causes corresponding stress on the downstream part of the intake manifold. Particularly, a central section between the first bank and the second bank in the downstream part tends to receive, in a concentrated manner, the force transmitted from the first cylinder head and the force transmitted from the second cylinder and thus may be damaged.